Adolph feank



' UN TED STATES P TENT OFFICE.

ADOLPH FRANK, OF CHARLOTTENBURG, PRUSSIA, GERMANY.

PRODUCTION OF SULPHITE SOLUTIONS.

SPECIFICATION forming part of Letters Eatent 1 To.'376,190, dated January 10, 1828.

Application filed Jl liy 21, 1887. Serial 1T0. 244,914. (No specimens.) Patented in England October 18, 1886, No. 13,286; in

Canada December 2-1, 1886, No. 25,613, and in Austria-Hungary April 1, 1887, No. 40,472 and No. 5,831.

T at whom it may concern:

Be it known'that I, ADOLPH FRANK, doctor of philosophy, a subject of the Emperor of Germany, residing at Charlottenburg, Prussia, German Empire, have invented certain new and useful Improvementsin the Production of Sulphite Solutions; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention consists in aprocess for producing acid-sulphite solutions, and obtaining at the same time calcium sulphate, (annaline, pearl-hardening, or pearl-white,) for which I have received foreign patents as follows: Canada December 24, 1886, No. 25,613; Great Britain October18, 1886, No. 13,286; Austria- Hnngary April 1, 1887, No. 40,472 and No. 5,831. g

In the preparation of these acid-sulphite solutions I employ calcium monosulphite, which may be obtained byany desired or known process, (preferably by the process described in my application for patent filed on or about the 18th of October, 1886, Serial No.

. 216,560,) and treat the same with free sulphuric acid, or with sulphuric acid combined 2(CaSO H,SO

Calcium sulphite. Sulphuric acid.

Calcium sulphite. Sodium bisulphite.

with sulphate of sodathat is to say, sulphate of soda.

In carrying out my invention I mix the calcium monosulphite with water and sulphuric acid, the latter in such proportion as will be necessary to bind one-half of the lime in the solution with a view to its conversion into calcium sulphate. The other half of the lime remains in combination with the sulphurous'acid of the calcium monosulphite, and forms a calcium sulphite soluble in water, while the calcium sulphate precipitates and the acid calcium sulphite goes into solution.

By the use of sulphuric acid, whether free or combined, I am enabled to obtain a valuable by-product-namely, the annaline used in the manufactureof paper. On the other hand, I have discovered that calcium sulphate is less soluble in an acid-sulphite solution than it is in water. The separation, therefore, of the sulphate is more completethan by any other process.

The reactions in the process-when, for inacid phite-are ill ustrated by the following formula, according to which the amount of sulphuric acid required relatively to the amount of calcium monosulphite employed may be readily calculated:

(CaSO,, H,SO,) CaSO, A- Calcium bisnlphite. Calcium sulphate.

The following formula shows the reactions of this mode of procedure, and also affords the means for calculating the amount of sodium bisulphite to be employed:

The resulting annalin is, asabove described, either case an acid-sulphite solution is obseparated from the solution and'washed, In tained from the calcium monosulphite, which stance, the acid solution is to contain bisulmay, for example, be employed in the suland obtaining calcium sulphate, which conphite-solution process. sists in treating the calcium monosulphitc In case the acid-sulphite solutions are not to with sulphuric acid or with acid sulphate of contain bisulphite only, a less quantity of sulsoda, as set forth. :5 5 phuric acid is employed for the less acid so- In testimony whereof I affix my signature in lutions and a greater quantity for the more presence of two witnesses. acid solutions to be obtained.

Having described myinventi0n,what Iclaim ADOLPH FRANK is- Witnesses: IO The described process of producing acid- 13. ROI,

sulphite solutions from calcium monosulpliite CARL BEZA. 

